The overall aim of this proposal is to develop and to evaluate methods for reducing the risk for hospitalized patients of acquiring urinary tract infections associated with the temporary use of indwelling bladder catheters. We believe that effective control measures must be based on a sound understanding of the epidemiology and pathogenesis of catheter-associated infections. Toward this objective, we have established a program for the daily bacteriologic monitoring of urinary drainage systems, and, using a unique computerized medical records system developed techniques for implementing prospective randomized, controlled studies of preventive methods. We have identified bacterial colonization of the urethral meatuscatheter junction as an important risk factor for later bacteriuria. In the proposed studies, we will use our monitoring system to evaluate the epidemiologic determinants and dynamics of meatal colonization with potentially pathogenic bacteria, determine the relative importance of endogenous versus exogenous sources for bacteriuria, and devise new strategies for blocking ascending infectrion in the space between the catheter and the urethral epithelium. We also propose to define the epidemiology of catheter-asso-ciated infections due to gram-positive cocci and yeast, which are of growing importance and have received less attention in previous work. Specific intervention studies that are planned include evaluations of hydrophilicpolymer coated silicone catheters in conjunction with intra-urethral disinfection with povidone-iodine gel and daily meatal care using a polyantibiotic cream; of periodic instillation of hydrogen peroxide into drainage bags; and of continuous bladder irrigation with povidone-iodine solution.